Alcatel

Alcatel Lucent

Alcatel N.v.

Avanex Corporation

Alcatel Submarine Networks

Patrick Brindel

Olivier Leclerc

Denis Penninckx

Emmanuel Desurvire

Thomas Ducellier

Gabriel Charlet

Alexandre Shen

Fabrice Devaux

Christopher Janz

Sebastien Bigo

Bruno Lavigne

Annalisa Morea

Massimiliano Salsi

Jean-Claude Jacquinot

Bruno Dany

Elisabeth Brun

Annaick Trotel

Gaelle Le Meur

St&eacute;phanie Barre

A method for activating a card within a communication network, making it possible to minimize the power consumption cost of putting the card into effect. The method consists of seeking out, and activating as a priority, cards which are located in already-activated receptacles. A receptacle may be a tray or cabinet in a predetermined search range corresponding to one or more nodes of said communication network.

Method for activating card within a communication network

Provided are a method for processing optical signals and a transmitter for the signals adapted for an ultra-high bit rate. The method uses an optical pulse stream with a carrier suppressed return to zero (CS-RZ) format to be obtained from an optical modulator that is driven using a combination of two sinusoidal electrical voltages, one at a frequency f and the other at the third harmonic 3f of the frequency f.

Method and system for generating CS-RZ pulses showing narrow width of bit duration

A multichannel wavelength-division multiplex fiber optic transmission system includes an optical transmitter and an optical receiver connected by an optical line including at least one optical fiber and at least one set of channel regenerators. Successive regenerators regenerate respective groups of channels forming a subset of the set of channels.

WDM regenerated transmission system

The invention is also related to devices for a synchronization of data in an optical WDM transmission system, consisting of the following parts: A wavelength demultiplexer () for demultiplexing the incoming data stream in the synchronizer, delay lines () for the individual wavelength channels, a multiplexer (), a modulator () modulated by a high frequency clock signal () and at least one photodetector () tapped to output line (B) where the photodetector () is connected to an electronic control circuit () which is connected to the findividual delay lines () for an automatic delay control.

Method for adjusting time delays and device for synchronization of channels in a WDM system

The present invention propose to use an optical multiplexer associated with an optical clock as a wavelength converter. Each RZ coded tributary will be carried by a single wavelength (channel) passively interleaved with the others without interferometric interaction hence achieving a not necessarily perfect OTDM. This input data stream as optical data signal composed of different wavelengths is then launched on at least one data access of said optical multiplexer used as a wavelength converter. An optical clock at the desired bit-rate is launched on the probe access of said optical multiplexer synchronously to the multi-wavelength data stream. At the output, the initial clock wavelength is converted on data signal using the gain conversion property of the optical multiplexer. In such a way, a data stream of substantially higher bit-rate is obtained while due to a very precise synchronization a lost of data is minimized.

All-optical high bit-rate multiplexer

The present invention provides a generator of a CS-RZ optical clock signal at a predetermined clock frequency. The generator contains a first laser source and a second laser source which respectively produce first and second continuous lightwaves, where the laser frequency of at least one of the sources is adjustable. The generator also contains a coupler disposed to receive the first and second lightwaves and forms optical beats at a beat frequency. An opto-electronic feedback is used to servo-control the adjustable-frequency laser source(s) in such a manner that the beat frequency, which is equal to the difference between the laser frequencies, is substantially equal to the clock frequency.

CS-RZ optical clock signal generator, and a resynchronized optical multiplexer containing such a generator

Device for regenerating optical signs

To delay optical signals precisely and continuously in a very small dynamic range, a device for applying a time-delay to optical signals includes a first phase modulator to receive an input optical signal carried by an original center wavelength and to apply a first stage of phase modulation to the carrier wave of the input signal to supply a first intermediate signal carried by a modified center wavelength, a delaying dispersive member having chromatic dispersion to receive the first intermediate signal and to supply a second intermediate signal, and a second phase modulator to receive the second intermediate signal and to apply a second stage of phase modulation to the carrier wave of the second intermediate signal to supply an output signal carried by the original center wavelength. Applications include optical telecommunication systems, in particular converting wavelength division multiplexed signals into time division multiplexed signals and regenerating wavelength division multiplexed signals.

Device for applying time-delays to optical signals

Known optical power equalizers receive an optical main input signal modulating between high and low input power levels. The optical power equalizers emit an equalized optical main output signal modulating between high and low output power levels, where at least one of the two sets of high and low power levels is equalized to one high or one low output power level. Such devices can comprise at least one gain-clamped semiconductor optical amplifier that operates about its saturation range. The optical power equalizer receives an amplifier input signal, which has one or more modulated portions, and emits a modulated amplifier output signal. According to the invention the dependence of the gain-clamped semiconductor optical amplifier's gain on the power of the amplifier input signal is adjusted such that the high input power levels of the amplifier input signal are equalized into the one high output power level of the amplifier output signal.

Optical power equalizer

An optical module advantageously uses optical conversion fibers not only for a single channel but for sets of channels that are, in a specific way, selected from a multi-channel wave division multiplex (WDM) grid. The sets of channels are defined such that four wave mixing is negligible or has a negligible effect. The optical module has a demultiplexer, a multiplexer, and parallel optical conversion fiber portions that are arranged between the demultiplexer and the multiplexer. Each of the parallel optical conversion fiber portions has a specific dispersion map and transmits a different set of channels of the multi-channel WDM grid. These channels are regularly spaced from each other.

Optical module for multi-channel wavelength multiplexing

To resynchronize input optical signals with different optical carrier frequencies f , f a delayed optical signal is created by applying a variable time-delay to one of the signals. A combination signal is formed by coupling measurement optical signals respectively obtained from the delayed signal and from the other input signal. A mixed signal is formed by injecting the combination signal into a non-linear optical device. A filtered signal is formed from the mixed signal using a filter tuned to an optical frequency f equal to p.f &plus;q.f p and q being relative integers such that the frequency f is different to the frequencies f and f of the carrier waves. The variable time-delay is controlled in accordance with a control electrical signal representative of the average value of the intensity of the filtered signal. Applications include wavelength-division multiplex optical communication systems.

Optical signal resynchronization method and device

The invention relates to an optical fiber transmission system using soliton signals with wavelength division multiplexing in which the wavelengths, &lgr; to &lgr; , of the various channels of the multiplex are selected in such a manner that at least one point of the transmission system, the difference between the bit times of any two channels of the multiplex is substantially a submultiple T/N of the clock period. The invention proposes placing a synchronous modulator at said point to modulate the soliton signals at a frequency N/T which is a multiple of the soliton clock frequency 1/T. In a frequency allocation scheme that ensures that the bit times of the channels are synchronous at an interval ZR, this makes it possible to modulate all of the channels at intervals that are submultiples of Z by using modulation frequencies that are multiples of the clock frequency.

Optical fiber transmission system using soliton signals with wavelength division multiplexing

In an optical modulation method a wave to be modulated and an optical control wave are injected simultaneously and colinearly into the same waveguide formed in a semiconductor diode that is reverse-biased so that the waveguide and the diode constitute the semiconductor part of an electro-absorption modulator. The wavelength of the control wave is shorter than that of the wave to be modulated. The impedance at the terminals of the diode is sufficiently high to enable amplitude modulation of the control wave to be transferred to the wave to be modulated. Applications include fiber optic telecommunication systems, in particular for resynchronizing solitons.

Modulation method and semiconductor optical modulator

In an optical transmission method solitons are transmitted through a succession of fibers in which their intensity progressively decreases. To limit distortion of the solitons, this decrease in their intensity is accompanied by a decrease in the chromatic dispersion of the fibers. In accordance with the invention, the succession of fibers includes at least a first fiber featuring continuously longitudinally decreasing chromatic dispersion. Subsequent fibers feature respective longitudinally constant chromatic dispersions forming a longitudinally decreasing sequence. Applications include telecommunications.

Optical transmission method and system using solitons

A laser is biased in the vicinity of the bend in its characteristic curve. It also receives, in electrical form, a base wave applied to an input of the generator and a local wave provided by a local oscillator, and it mixes these waves by adding their frequencies so as to modulate the lightwave that it emits. The invention is particularly applicable to telecommunications systems.

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Longpont S/Orge, France

Patrick Brindel